Disc or portable drive
The images may be in a folder named DICOM, IMAGES or STUDIES. The supplied disc may also contain a separate viewing application, which is not required for this browser viewer.
Free tools · Guide
How to Use the DICOM Viewer
Find your imaging files, open them in the viewer and use the basic display controls.
Hospital imaging is commonly supplied in DICOM format on a disc, portable drive or secure download. A CT or MRI examination will usually contain many image files rather than one ordinary photograph.
This browser viewer is intended for basic review. It is not a diagnostic workstation and does not provide a medical opinion.
Last reviewed October 2026
§ 01
Find the Imaging Files
Open the disc, drive or downloaded folder using File Explorer on Windows
or Finder on macOS. Look for folders containing files ending in
.dcm, or files with no extension.
Downloaded archive
If the download is a ZIP archive and the viewer does not open ZIP files directly, extract it before selecting the images. A PDF is usually the written report, not the complete imaging examination.
Complete examination
CT and MRI examinations commonly contain many images and several series. Keep the original folder structure where possible.
§ 02
Open the Study
Open the /free-dicom-viewer DICOM viewer and choose the files or folder containing the examination.
Choose files
Select one or more DICOM files. For a CT or MRI examination, select all relevant files rather than a single image.
Choose a folder
Where supported by the browser, selecting the complete folder is usually the simplest way to open a full examination.
Drag and drop
On a desktop computer, files or folders may also be dragged onto the viewer. Use the selection buttons on a phone or tablet.
§ 03
Use the Viewer Controls
Move through images
Use the slice control, arrow buttons, mouse wheel or touch gesture, depending on the device and browser.
Window and level
Window width controls the displayed contrast. Window level controls the centre of the displayed brightness range. Suitable settings vary by modality, sequence and tissue.
Zoom and pan
Zoom enlarges the image. Pan moves around an enlarged image without changing the underlying data.
Invert
Invert reverses the displayed black and white values. It does not alter the source file.
Reset
Use Reset if the image becomes difficult to see after adjusting the display.
§ 04
Clinical Information in DICOM Files
DICOM files may contain patient names, dates of birth, hospital identifiers, examination dates and other clinical information, even when those details are not displayed on the screen.
The viewer is intended to process selected files locally in the browser. This should be confirmed by technical testing of the deployed viewer, including network activity, analytics, error reporting, browser storage and third-party scripts.
§ 05
If the Study Does Not Open
No images found
Confirm that the selected folder contains DICOM images rather than only a PDF report, screenshots or the disc's viewing program.
Unsupported file
Some compressed, encrypted, multi-frame or vendor-specific objects may not be supported. Try the viewer supplied with the examination or request a standard DICOM export.
Only one image appears
Check whether only one file was selected. A complete CT or MRI examination usually contains many files.
The image appears too dark or bright
Use Reset, then adjust window and level gradually. There is no single correct setting for every CT or MRI examination.
Performance is poor
Large studies may exceed the available memory of a phone, tablet or older computer. Try a current desktop browser or the viewer supplied by the imaging provider.
§ 06
Common Questions
Are my images uploaded?
The viewer is designed to process selected files locally in your browser. Before using identifiable clinical images, confirm that this remains true of the current implementation and that no analytics, error-reporting or other service receives file contents or DICOM metadata.
Is the viewer free?
Yes. No account or payment is required.
Can I use a phone or tablet?
The viewer may work on a recent mobile browser, although large studies and some DICOM formats are better handled on a desktop or laptop.
Why can I see only one image?
A CT or MRI examination usually contains many files and may include several series. If only one file was selected, the viewer may have received only one image.
Can I obtain a medical opinion from the viewer?
No. The viewer displays images but does not interpret them. Clinical or medicolegal review requires the complete examination, relevant prior imaging and clinical information.
/free-dicom-viewer
Open the DICOM viewer